This invention relates to video cameras suited for use with photo-cameras or for picking up still pictures, video camera devices for recording video signal output from a video camera in a VTR or a still image recorder, and adapters suited for use with such video camera devices.
Using a video camera, it is possible to pick up still pictures as well as motion pictures. However, it is often desired to use a photo-camera together with a video camera. For example, it is thought to operate a photo-camera shutter while picking up a motion picture with a video camera.
In the meantime, where the camera is used as a monitor camera, it is convenient if the photo-camera shutter is automatically operated when the status of the foreground object zone is changed with a movement of a man or an object.
Further, it is convenient that when operating a photo-camera shutter the output video signal of the video camera is provided with a special effect indicative of the shutter operation. This permits, for instance, the presence of any kind of picture to be readily known at the time of video signal reproduction in a VTR.
Further, when strobic light is emitted at the time of the photo-camera shutter operation, charge accumulated in the image pick-up device is increased suddenly with the strobic light emission, and also the level of the image pick-up signal from the image pick-up device is suddenly increased. However, usual irises or AGC circuits in video cameras are too slow in response to be able to follow instantaneous image pick-up signal level changes.
Therefore, when the image pick-up signal level is suddenly increased, the AGC circuit operates with the same gain as when the image pick-up signal level is not increased, thus resulting in an excessively high image pick-up signal level. This may cause what is commonly termed saturation. This is so not only in the case of using the strobic light emission but also when the image pick-up signal level is occasionally suddenly increased.
Further, when light from a foreground object, for instance, is insufficient to photograph a still picture using a video camera, if only an image pick-up signal corresponding to the object which is made to provide sufficient light with strobic light emission can be recorded with a still image recorder, it will be very convenient because in this case only a high quality image pick-signal can be recorded with the still image recorder.
Further, if light from the object is insufficient when picking up a still picture using a video camera, it may be thought to increase the sensitivity by increasing the charge accumulation time such as to provide sufficient charge accumulation in the image pick-up device. When picking up a still picture, increasing the charge accumulation time does not result in such inconvenience as image deviation. Depending on the amount of the object light, however, excessively increasing the charge accumulation time results in such inconvenience as saturation of charge accumulated in the image pick-up device.
Further, in case the object light is insufficient when picking up a still picture using a video camera, it may be thought to use a strobe to provide for sufficient charge accumulation in the image pick-up device. However, when a strobe is used, it is dark (i.e., the illumination intensity is low). Therefore, the iris is open, and the AGC circuit is in its operative period. Usually, the response of the iris is slow, and great light due to strobic light emission is incident on the image pick-up device. For this reason, the use of a strobe may result in the saturation of charge accumulated in the image pick-up device.
Meanwhile, an output video signal from a video camera may be supplied to a VTR for motion image recording or supplied to a still image recorder for still image recording. There is a still image recorder, which uses a DAT proposed earlier by the present applicant (see Japanese Patent Application Laid-Open No. 161661/1990).
Usually, a single recorder is connected to a video camera for recording. This means that every time the motion or still image recording is made, the recorder connected to the video camera has to be replaced. This is very cumbersome for the user. Accordingly, a plurality of different recorders may conveniently be connected to a video camera such that they may be automatically selected in accordance with the user's video camera operation.
For the automatic selection of a plurality of recorders, it may be thought to cause selective output of recording control signals corresponding to the respective recorders to be supplied to an adapter so as to effect selection of the corresponding recorder.
Where a plurality of recorders are connected via an adapter, it is necessary to output recording control signals individually corresponding to the respective recorders. However, where a single recorder is connected directly, it is only necessary to output a fixed recording control signal irrespective of the kind of recorder. In this case, it is convenient to be able to automatically determine one of the recording control signals that is to be provided.